Manufacture of base-exchange substances



Jan. 13, 1931.

S. DAHL-RODE MANUFACTURE OF BASE EXCHANGE SUBSTANCES Original Filed May 25, 1925 i cAz/sr/c soon sour/701v 34a i 7'0 WASTE 6 I. K A W? W L EACH ING TA NK I Z o \lllL llllL olllL 1' llll Ill lllllllllllllll I.

a, YANIA';

svn'iii BAKE-3015B,,OFPHILKDEEDPHIA, PERNSSIZLVANIA, Assieiyioaro-oocH ANEooR I POBATION, "F PHILADELPHIA, PENNSYLVANIA} A CORPORATION .02 rEN'NsYL My invenubnieietes to a mar-(55 5mm "uiaeturing basegexchange substanoes orarti- I ficial ,zeol tes,"u t1l1zable for various purpose s,"including the softening offwater for use in l-au v a and for k ndred purposes,

ndries, hotels, as boiler feedwater,

Tl appliicationis fin part a -continiiation "Q -'a' n understanding my method and "for anillustration of a nodeof carrying it.

. into ;e:ecution,lreference may b ehad to the accompanying drawing, V, which 18 largely a 1 'dia s ramniaticf viewf of a systemutilizable for. the practice of my invention."

Thereiis" utilized as a"startihgYniaterial a v I other}'than'that"whichis'combined with the the slag from the furn'aces or blast ,furnaces in which there are produced 'f1OI11 l3lielI' compounds 'or ores, ron, manganese and the like. Any suitable slag-niaybe utilized Iif containingin suitably large proportions silica, aluminum and calcium, .niagn'esium or other metal, which upon treatment of the j v characterhereinafter described will "yield base-exchange compounds, such as double compounds of sodium and calcium alumi- The slag is from the furnace, into water, therebyefl ect in'g des rable porosity and character stics favorable to subdivision into'j-fine grams or powder.

Foran understanding of inilentiom'dt illbe described With regardfio; its application to the treatment of iron ,furnace islag.

The iron furnace slag, preferably watercooled as aforesaid, is ground or pulverized,

in a ball mill or equivalent, to ,approximately to 100 mesh," or finer. The pulverized slag 1s delivered as from ahopper or funnel 1 into the treatin andldr in 7 b 23 chamber" or kettle T, which ;is p referably i not shown.

pro vided with agitating means,' fsuch 'asan ag1tato112, ofany suitable 'characterfor construction, actuated or rotated by the 3 driven by any suitablejsource or powe There "isfintroduced into the eating chamber T, Y hiw th passage 4,. caustic soda, or ,-'a: 1y suitable these ,alk'a' es oi' myapplication"Serial No. 757,602, filed zDecemblel. 1924 "recovery MANUFAGTURE or eesn nxorranensunsmiqoiis j v droxide rsodiunifpotafssiuin or othercari bonategoria mixture ofany twogor more of treatingchamber T, the proportions,

to r0120; 1 The" 'niixture is continuously for example, by

I Water'is iritroduced iiito i r "bi/.155 e ght, ofv pulver zed slag', caustmsoda'nnd [Waterpreferably being ofthe Order QflOO slowly fagiteteclor stirred by the agitator 2, and ts temperature raised, by heatja'pplied .in any suitable manner, as,

combustion inthe furnace For aperiodf of the order ol -30 minutes the mixture is kept" at or nearitslboiling point, and thereafter the" application of heat is continued" to evaporate ofi' substantially all of the, Water,

product. 1,.Tlief product is; dried, preferably 7 within the chamber [1, at a tempe'rature hazel nutsjor marbles, and smaller, the size of the-pieces depending to considerableexftentflu'pon'the'method and efiect'iveness of the agitation.

jveri'zedjslag with caustic soda or equivalent, there isformed abase-exchange substance or artificial z'eolite comprising, forexarnple,

double eloinpounjds' of, so ium and caleiuni 'aluminumisilicate, which, however, is preferably. further' treated, as hereinafter de;

scribed, to effect a refined productfancl, for f a portion ofthe caustic soda or other alkali utilized inthe reaction;

The dried product is deliveredironi the treatin'gchan ber T, as through the chute 5, to the hopper 6, from hichlit passes into'the 13, the aforesaid treatment of the nul- Sifter i11 Whichthe pieces orparticles of clifferent'si'ze's are separated from each other.

The ultimate materialis .p referably ingra n- "ules -passfing through 20 inesh-a1f1d' retained s, f

'upon40. inesh soreensl Granules of this size.

for further treatment." The fine's, -0r Jpar- .may be separated by the screening 'inechan s'm o'r'sifteri and delivered nto therecepta'cle 8, from Wh'1ehth'eyare later wlthdrawn are delivered into the receptacle 9, from which tlieyare withdrawn and returned to the hopper or funnel 10, from whichthey may be delivered into the treating chamberT into mixture with a further or new batch of pulverized slag, alkali and water, the tines so in mixture being substantiallyneutral with arespect thereto, but due to the subsequent drying process in thechamber T are in effect 111- cluded or incorporated in; larger masses of i {the crusher o1" mill'13 preferably of such character as to effect as large a percentage as possible of granules of the'desired size, as, for example, 20-40 mesh. The crushed 'material is delivered from the mill 13, as to the hopper 14;, and returned to the hopper 15, from which it is again passed through the screening apparatus 7, and any material coarser than 20-40 mesh again finds its way "to the mill 13, and after crushing is returned to the sifter 7 V The granules of desired size, as 20%0 mesh, are delivered from the container 8 into the leaching or treating tank 16, which is preferably provided with agitating means. lVater,'preferably hot, is circulated throughthe leaching tank from tank 20 through pump 21 and back through pipe 22, accom panied preferably by agitation in tank 16. The granules are first treated in the tank 16 with that amount of water required in the treating chamber T to make up a mixture with pulverized slag of the proportions above described. As much as possible of the alkali or caustic soda is leached from the particles in the tank 16 to effect an alkaline liquor as highly concentrated as possible. This liquor is withdrawn from the tank 16 and delivered through pipe 19 into the alkali storage tank 17, from which itais withdrawn as required anddelivered into the tank T, in the aforesaid proportion, through the pipe 18, into mixture with pulverized slag, suitable additional amount of alkali introduced through passage 4, and fines returned from the receptacle 9.

ifter removal of the more concentrated alkali solution from the tank 16, the granules therein are further leached by additional or fresh water, preferably hot, which removes more'alkali or caustic soda, which may be drawn off through the pipe 19a to waste, or to suitable destination for further recovery of alkali if found economically desirable.

The base-exchange material or artificial zeolite at this stage may still contain some alkali, as caustic soda. It will also generally contain calcium, much of which may be in messes the form of calcium oxide or hydrate, which it 1s desirable shall be removed. lhe alkali and the undersirablecalcium compounds are removed by treatment of the zeolite granules,

preferably still within the tank 16, with a weak acid solution, as, for-example, asuit ably dilute solution of acetic or equivalent org ganic or weak acid. p

Acetic acid solution, preferablyhot, isad- 'vantageous for treatment atthis stage, for

it will neutralize the alkali or caustic soda and will convert the calcium compounds into highly soluble calcium acetate, which is easily washed from the zeolite; and furthermore, acetic acid is not likely seriously to attack or dissolve the zeolite itself.

The acetic or other organic or weak acid solution is prepared in the tank 20 by the introduction of the acid and dilution water, and utilized preferably hot, heat being applied in any suitable way, as, for example,by introduction of steam. The hot solution of acid .is circulated b the um) 21 driven by motor, M, through the tank 16, from and back to tank 20, to effect circulation through and agitation with the zeolite granules to neutralizethe alkali or caustic soda, and, in addition, converting the calcium compounds to be removed into calcium acetate, or calcium salt of other organic or weak acid utilized and whose calcium salts are Watersoluble.

, The acid treatment is continued until the aforesaid reactions are more or less complete,as may be suitable or desirable. The reaction may be continued until a sample of the granules, washed with fresh water, and pulverized, does not show alkali or free alkali when tested by suitable indicator, as, for example, phenolphthalein. In some cases, however, as, for example, when the zeolite is to be utilized for softening boiler feed water where slightalkalinity is not harmful, the aforesaid acid treatment'm'av be discontinued before the alkali is completely neutralized.

After the acid treatment above described, the'granules are washed Within the tank 16 withcold water to remove the soluble products of reaction of the acid with alkali and calcium compounds. The washing'is continued until the wash'water no longer shows calcium when tested with suitable reagent, as, for example, sodium oxalate, which, as well understood, forms a precipitate of calcium oxalate. 7A lesser degree of refinement. however,may in some cases be suitable or desirable, and in such event the Washing need not be carried to the extent described. However, in general, the zeolite is of higher grade .when'substantially all of theunde sired calcium compounds have been removed.

After the granules have been so washed, practically all of the calcium compounds mechanically held by or within the zeolite have been removed, but the zeolite is now a calcium zeolite inthesense that in addition to the sodium or equivalentv aluminum silicate it comprises calclum aluminum I silicate. Inasmuchasycalciumcompoundsare :to be removed from water to bev softened ,flit is: desirable that thealunnnuln silicates o fjthe Zeolites" shallbe, "Wholly orl largely those ref sodium'," In eonsequence,; the aforesaid cal cium zeolite is notr in condition efficiently [to i remove the calcium 1 coinpou ndslfrom' Water to be. softened, and ithe zeolite isin what may begterined the vifiX-llflllsfiedi COQClitlOIl,

as it had been usedin softeningwater con-t ,tainingcalcium com-pounds, withfthe result that the calcium; in the water hadbeen ex changed for sodium ofthe sodium} aluminum silicate; and inasmuch as; itis desirable to ship or market; the, zeolite ,in' condition best suitedfor soften ng water,1the calcium; zeo-' lite is subjected tothe Qactfion of a solution o t, sodium chlor de, or -equ1valen t salt of a metal of the potassium group, mnchinzthe sa ne inanner as enhaustedaeolite is regenerated aft-etuseupon hardwater For this purpose, br ne or-sodlum chloride solut on,

which maybe preparedvor contained in the tanlrQO, is circulated therefrom by the pump 21 throughtank 16, where thegranules may I be agitated in the presence of the brine solution to reflect exchangeof sodiuinrfor the calcium of the zeolite;

The treatment ofzeolite sodium chloride orequivalent asaboire'indicated is enhanced by boiling the brine or equivalent solution whilerinacontact withthe ezeolite granules. The replacement of the calcium by sodium: or equivalentin the bi-frnetal 'sili cate, .as described, is further enhanced by acidulating the brine; solution, ,cold or, hot,

as by addition of acetic: acid or, equivalent. For example, about two to three pounds of zeolite may be treated with a twenty per cent sodium chloride solut1on in Water containing approximately one and, one-half acetic acid.

pounds of sodium chloride, with an addition ofabout fifty cublc centimeterstof. glacial The boiling ofthe salt solution Whilein contact with the Zeolite may be continued .for

any suitable time, foreXample, for about 0nc- .halfto about oneand one-half hours. The

salt solution may gthen be separated or drained off and the 'zeolite granules again boiled with salt solution for another suitable period, as of thefordcr oiione-half to one; and one-half hours". Either or both oil these successively used. brine solutions may be acidulatcd as by acetic acid orequivalent, as above described. a p The zeolite' after treatment with the brine solution is subjected-t0 Water to remove brine, and then, forconvenience of shipment, may be withdrawn from the bottom of the tank 16 into the drain box 23, where most oi the solution or water is drained from the material, which, if desired, may be left exiposedtoithe ai -rarefied drying before ;ment.

i contain approximately 20' per 'centmoijsture.

Ifallthis moistureisdriven off,; as by dry-,

ing'at a temperature. slightly above theboil-'-- .g point ofwateiythe zeolitemaylose some .sofitsexchange value, butit'is stilleffectlve, 'nnd hasa lngh exchange value, but the eX- rchange value is not sogreat as in the case Where the dryinghas not been carried to completion It, has comparatively 3 high I base-exchange Theze-olite produced as herein described has at specific gravity o'fgapproximately;1966* to about 2.4."14Itsgra1ns orgranules are hard.-

value, approximately five times as great as the zeolites made from glauconite or: green "sand commonly usedfor llle purposes. My zeolite has further advantage in thatit does not cause-discoloration(if-water, as is frequently the case nthe use of ZGOlltfi made from green sand or fg'laucon'ite,"particularly if not properly-treated; My zeoliterwell withstands theaction of hot water, It is:

'affected tolessiextentlby water to be softened which-is; slightly acid'tha-n are zeolites pro-v duced .byprecipitation or fusion 1 a and when the water to be softened is slightly acid the water is notfdis'colored byimy material as in the caselofpthe glauconrte or green sand type.- a

For'the sake o'flbrevityin the appended 7 claims, the term ironifurnace slag is eniployed generically to include iron, man

ganesexand equivalent furnace slags-o f. the

characterherein described; the term ,caustic sodalis employed *generically to include I caustic soda or equivalent alkalies of the p solution of acetic acid.-

and caustic soda, drying the reaction product, washing the dried product, andtherea-fter subjecting'the Washed product to a solution "of acetic acid;

4.;In ,theart ofproducing base-exchange substances, the, method which comprisesefiectingreaction between iron 'furnace slag" equivalent organic or i a r 1. V 6.,111 the art oi: producing base-exchanp substances, the method which COD'LPFISGS' efiectrng reaction between iron-furnace slag and caustic soda, drying the reaction product and subdividing it into granules, washing the granules, and thereafter subjecting them to a solution of acetic acid.

5. In theart of producingbase-exchange substances," the method which 7 comprises effecting reaction between iron furnace slag and caustic soda, drying the reaction prod uct, thereafter treating said product with a solution of acetic acid, and thereafter washing the product.

6. In the art of p'roducin base-exchange substances, the method which comprises effecting reaction between iron furnace slag and caustic soda, removing undesired compounds by application of organic acid and thereafter subjecting the pr-oductto a hot solution of sodium chloride. I

7. In the art of producing base-exchange substances, the method which comprises j elfecting reaction between iron furnace slag and caustic soda, removing undesired comsubstances, the

pounds, and thereafter subjecting the product to a solution of sodium chlorideacidulated with organic acid.

8. In the art of producin base-exchange 'method which comprises effecting reaction between iron furnace slag and caustic soda, removing undesired compounds, and thereafter subjecting the product to a hot solution ofsodiuni ulated with organic acid.

9. In the art of producing base-exchange substances, the method which comprises eifecting reaction between iron furnace slag and caustic soda, removing undesired compounds, and thereafter subjecting thefprodnet to a solution of sodium chloride acidu lated with acetic acid.

10. In the art of producing base-exchange substances, the method which comprises effecting reaction between iron furnace slag and caustic soda, removing undesired compounds, and thereafter subjecting theproduct to a hot solution of'sodium chloride acidulated with acetic acid.

V 11. In the art of producing base-exchange substances, the method which comprises effecting reaction between iron furnace slag and caustic soda, drying the reaction procluct, treating the reaction product with organic acid solution, and thereafter subjecting the product to a hot salt solution.

1.2. In the art of producing base-exchange substances,the method which comprises offecting reaction bet-ween iron furnace slag andcaustic soda, drying'the reaction prod:

not, treating the reaction product with acid 7 solution, and thereafter subjecting the prodnot to a salt solution acidulated with organic acid. V

13. In the art of producing base-exchange substances, the method which comprises effecting reaction between iron furnace slag chloride acid- 7 not, treating the reaction product with acid solution, and thereafter subjectingtheproduct to a hot salt solution acidulated with acetic acid. 9 1

14. In the art of producing base-exchange substances, the method which comprises effecting reaction between ironfurnace slag and caustic soda, drying the reaction product, thereaftertreating the reaction product with acetic acid solution, and thereafter subjecting the product to a salt solution acidulatedwith acetic acid.

15. In the art of producing base-exchange substances, the method which comprises effecting'reaction'betweeniron furnace slag and caustic soda, drying the reaction product,'thereafter treating the-reaction product 'with acetic acid for removal of undesired compounds, and thereafter subjecting the product to successive washings by hot salt solution;

16'. In the art of producing base-exchange substances,' the method which comprises effecting reaction between iron furnace slag and caustic soda, drying the reaction product, thereafter treating the reaction product for removal of undesired compounds, thereafter subjecting the product to washing by and caustic soda, drying the reaction product,

thereafter treating the reaction product with acetic acid for removal of undesired compounds, thereafter subjecting the product to washing by hot salt solution, and again washing with salt solution.

19. In the art of producing base-exchange substances, the method which comprises effecting reaction between iron furnace slag and caustic soda, drying the reaction product, thereafter-treating the reaction product for removal of undesired compounds, and thereafter subjecting the, product to successive .washings by salt solution, said salt solution in both washings being hot and acidulated with acetic acid.

' SVEIN DAHL-RODE.

and caustic soda, drying the reaction prod- 

